Dutch scientists have created a bacterium that can repair cracked buildings by turning cracks into stone, allowing concrete to heal itself and saving billions in repair costs |
Concrete is the backbone of modern civilization, supporting everything from homes and skyscrapers to bridges, tunnels and dams. However, even this extremely strong material has a costly weakness. Over time, due to age, weather, heavy traffic, and earthquakes, tiny cracks inevitably form, allowing water to penetrate and corrode the steel reinforcements inside. Repairing damaged concrete infrastructure costs governments and businesses billions of dollars each year. What if these structures could repair themselves the same way human skin heals after a cut? The once-far-fetched idea became a reality when Dutch microbiologist Professor Henk Jonkers developed self-healing concrete using bacteria that produce calcium carbonate, commonly known as limestone, allowing cracks to seal naturally and potentially extending the life of a building while reducing maintenance costs.
Who is the Dutch scientist behind self-healing concrete?
This breakthrough was pioneered by Professor Henk Jonkers, a microbiologist at Delft University of Technology (TU Delft) in the Netherlands. Unlike traditional civil engineers, Jonkes specialized in microbiology and wondered whether living organisms could solve one of the construction industry’s oldest problems.Inspired by the body’s ability to heal wounds, he spent years studying bacteria that could survive in extremely harsh conditions. His research ultimately led to the development of self-healing concrete containing dormant bacterial spores that remain inactive until cracks develop.Jonkers’ work gained international recognition after receiving support from a European research project and has since become one of the best-known examples of biomimetic engineering in the world.
How do bacteria repair broken buildings?
The secret lies in a group of naturally occurring bacteria from the family Bacillaceae, including species such as Bacillus pseudoconi and Bacillus coni. These bacteria are specifically selected because they can survive in the highly alkaline environment inside concrete.During construction, bacterial spores are mixed into the concrete along with tiny capsules containing nutrients such as calcium lactate. Under normal conditions, bacteria can remain dormant for decades because there is no moisture within healthy concrete.When cracks appear, rainwater can enter the concrete and activate bacteria. Microorganisms consume the nutrients and convert them into calcium carbonate, commonly known as limestone. This newly formed limestone gradually fills the cracks, preventing further water penetration and protecting the steel reinforcements inside the structure.Once the cracks are sealed and the moisture is gone, the bacteria go dormant again until they are needed.
What studies prove that self-healing concrete works?
One of the earliest landmark studies was “Applying bacteria as self-healing agents to develop sustainable concrete,” published in the journal Ecological Engineering. The study, authored by Henk M. Jonkers, Arjan Thijssen, Gerard Muyzer, Oğuzhan Çopuroğlu and Erik Schlangen, demonstrates that bacteria can successfully seal cracks by producing biologically formed limestone.Further research at TU Delft’s micro-laboratory and the university’s Department of Materials and Environment showed that the bacteria can survive inside concrete for years and can repeatedly repair small cracks after exposure to water.Another influential publication, Bacterial Concrete: From Concept to Market, authored by Henk M. Jonkers, explained how the technology evolved from laboratory experiments to pilot-scale applications, emphasizing its ability to improve the durability and watertightness of reinforced concrete structures while reducing maintenance requirements.Since then, researchers around the world, including teams in the UK, Belgium, China, South Korea and India, have validated and extended Jonkers’ work, making self-healing concrete one of the fastest-growing areas of sustainable construction research.
How much damage can bacteria repair?
Current versions of bacterial concrete can typically repair cracks up to around 0.5 to 1 mm wide, depending on the concrete mix and environmental conditions.While it sounds small, these tiny cracks are often the starting point for larger structural problems. By sealing them early, bacteria can prevent water, oxygen and salt from reaching the steel bars, significantly slowing corrosion and extending the life of the building.Researchers are now developing improved bacterial strains and nutrient delivery systems that can heal wider cracks and work for longer.
Could this technology save billions of dollars in repair costs?
Concrete is the most widely used construction material in the world after water. Aging infrastructure requires huge investments to repair aging bridges, tunnels, highways and public buildings, according to the American Society of Civil Engineers (ASCE).By automatically repairing small cracks before they become serious, self-healing concrete can significantly reduce maintenance costs, extend service life and minimize the damage caused by repair work.The technology is particularly valuable for repairing difficult or expensive structures, including offshore platforms, underground tunnels, dams, railway bridges, parking structures and marine infrastructure.As well as saving money, reducing maintenance work can also lower carbon emissions, as producing new cement is one of the world’s largest industrial sources of carbon dioxide.
Has self-healing concrete been used outside the laboratory?
Yes. Since its invention, bacterial concrete has been tested in several pilot projects across Europe.The Netherlands has incorporated self-healing concrete into experimental infrastructure projects, while researchers in Belgium, Italy and the UK have conducted field trials on bridges, tunnels and retaining walls.Inspired by Jonkers’ research, several companies have also begun commercializing bacteria-based self-healing concrete products for use in specialized construction projects. However, the technology has not yet been widely adopted in mainstream construction because it is still more expensive than traditional concrete. The researchers believe its use may become more widespread as production costs fall and long-term economic benefits become more apparent.
Why self-healing concrete could transform the construction industry?
For decades, engineers have been working to repair problems after concrete fails. Professor Henk Jonkers has turned this idea on its head by creating a material that can repair itself before serious damage occurs. His bacterium-powered concrete combines microbiology with civil engineering to provide a sustainable solution to one of the biggest challenges facing the construction industry.While scientists continue to refine the technology, the concept has changed the way engineers think about infrastructure. Rather than constantly repairing aging buildings, cities of the future could be built using materials that can quietly maintain themselves for decades, reducing costs, improving safety and making buildings more sustainable.
